Temperature effects – Campbell Scientific Sentek TriSCAN® Manual v 1.2a User Manual

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TriSCAN Manual Version 1.2a

Page 8

Salinity:

There are two levels at which resolution and accuracy may be considered with regard to the TriSCAN®
sensor:

•

Resolution and accuracy of the electronic sensor

•

Resolution and accuracy of the benchmarking (correlation of VIC to EC) procedure

The resolution of the electronic sensor, i.e. the smallest measurable increment, has been determined to be
as low as 1 microSiemen/cm (0.001 mS/cm) in dry soil conditions, and as high as 14 micoSiemen/cm (0.014
mS/cm) in saturated soil conditions.

The accuracy of the benchmarking of the VIC values to soil EC is dependent upon the degree of alignment
possible as limited experimentally. This is affected by many things, including the ability of the operator to
measure the physical EC, soil sampling technique and sample timing. In Sentek’s own field testing, strong
relationships (r2=0.9) have been achieved (refer Figure 8, Benchmarking section).

At Sentek’s laboratories, the accuracy of the sensor to predict the EC has been determined at ±8.06%
(range: 6.0 – 10.1%). This figure was determined through analysis of the inherent variability of discrete
salinity measurements as taken over a range of water contents from 4% (dry sand) to 20% (saturated) and a
salinity range from 0 to 4.9 mS/cm.

Temperature Effects

The precise temperature effects on TriSCAN data output are currently unknown. It is however, known that
there is a minor positive relationship between VIC and soil temperature. The TriSCAN model currently does
not include temperature correction.

In the field the graph pattern produced is easily discernable as a small temperature effect distinct from
salinity changes.